U.S. patent application number 12/481923 was filed with the patent office on 2010-06-24 for laser slope adjustment.
This patent application is currently assigned to Trimble Navigation Limited. Invention is credited to Geoffrey Kirk, Nicholas Talbot.
Application Number | 20100157283 12/481923 |
Document ID | / |
Family ID | 42265569 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100157283 |
Kind Code |
A1 |
Kirk; Geoffrey ; et
al. |
June 24, 2010 |
LASER SLOPE ADJUSTMENT
Abstract
Tools and techniques for estimating elevations, including
without limitation tools and techniques that employ mobile stations
with laser detectors for receiving a beam emitted from a laser
source and estimating an elevation of the mobile station based on
the received beam. In some instances, a mobile station may be
configured to identify, based on some or all of a variety of
factors, a situation in which the elevation of the detector is
likely to change to the extent that the slope of the emitter needs
to be adjusted to account for this change in elevation. The mobile
station may also be configured to inform the laser source that the
slope of the emitted beam should be adjusted. In response, the
laser source may adjust the slope of the emitted beam
accordingly.
Inventors: |
Kirk; Geoffrey; (Broomfield,
CO) ; Talbot; Nicholas; (Ashburton, AU) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Trimble Navigation Limited
Sunnyvale
CA
|
Family ID: |
42265569 |
Appl. No.: |
12/481923 |
Filed: |
June 10, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61139149 |
Dec 19, 2008 |
|
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|
Current U.S.
Class: |
356/28 ;
356/141.4; 702/150; 702/158; 702/166 |
Current CPC
Class: |
G01C 15/002
20130101 |
Class at
Publication: |
356/28 ;
356/141.4; 702/150; 702/166; 702/158 |
International
Class: |
G01P 3/36 20060101
G01P003/36; G01B 11/26 20060101 G01B011/26; G01B 11/22 20060101
G01B011/22; G01B 11/14 20060101 G01B011/14 |
Claims
1. A system for estimating an elevation of a vehicle, the system
comprising: a laser source, comprising: a rotating laser emitter
configured to emit a spot beam having a slope that is adjustable by
the laser source; and a first radio frequency communication ("RF")
transceiver; and a mobile station configured to be mounted on a
moving vehicle, the mobile station comprising: a laser detector,
comprising a substantially vertical array of laser sensors; a
global navigation satellite system ("GNSS") receiver; a second RF
transceiver; and a processing system comprising a processor and a
computer-readable medium having encoded thereon a set of
instructions executable by the computer system to perform one or
more operations, the set of instructions comprising: instructions
to establish an upper threshold value corresponding to a first
portion of the array of laser sensors; instructions to establish a
lower threshold value corresponding to a second portion of the
array of laser sensors; instructions to receive input data from the
laser detector; instructions to determine, based on the input data,
a laser strike location value corresponding to a portion of the
laser detector receiving the spot beam emitted by the laser
emitter; instructions to compare the laser strike location value
with at least one threshold value selected from the group
consisting of the upper threshold value and the lower threshold
value; instructions to determine, based at least in part on a
comparison of the laser strike location value with the at least one
threshold value, an amount by which the slope of spot beam emitted
by the laser emitter should be adjusted; and instructions to
transmit, via the second RF transceiver, a notification for
reception by the first RF transceiver, the notification instructing
the laser source to adjust the slope of the spot beam by the
determined amount; wherein the laser source is configured to
adjust, upon receipt of the notification, the slope of the spot
beam over a period during which the spot beam will not be received
by the laser detector, and to transmit a message informing the
mobile station of an adjusted slope of the spot beam emitted by the
laser emitter; and wherein the set of instructions further
comprise: instructions to determine, based on input from the GNSS
receiver, a position of the mobile station; and instructions to
calculate an elevation of the mobile station, based at least in
part on the adjusted slope of spot beam emitted by the rotating
laser emitter, the position of the mobile station, a position of
the laser source, and input data received from the laser
detector.
2. The system of claim 1, wherein: the set of instructions further
comprises: instructions to set a height of a tool on the vehicle,
based at least in part on the calculated elevation of the mobile
station device.
3. The system of claim 1, wherein the laser strike location is
selected from the group consisting of an absolute elevation and an
elevation relative to the laser detector.
4. The system of claim 1, wherein the mobile station is a first
mobile station, the system further comprising: a second mobile
station, comprising: a second laser detector; a second GNSS
receiver; a third RF transceiver; and a second computer system, the
second computer system comprising a second processor and a second
computer-readable medium, the second computer-readable medium
having encoded thereon a set of instructions executable by the
computer system to perform one or more operations, the set of
instructions comprising: instructions to determine, based on input
from the second GNSS receiver, a position of the second mobile
station; instructions to receive second input data from the second
laser detector; and instructions to calculate, upon reception of
the message from the laser source, an elevation of the second
mobile station, based at least in part on the position of the
second mobile station, a position of the laser source, the second
input data from the second laser detector, and the adjusted slope
of the spot beam emitted by the laser emitter.
5. A system, comprising: a laser source, comprising: a laser
emitter configured to emit a beam having a slope that is adjustable
by the laser source; and a first communication system; and a mobile
station, comprising: a laser detector; a second communication
system; and a processing system comprising a processor and a
computer-readable medium having encoded thereon a set of
instructions executable by the processing system to perform one or
more operations, the set of instructions comprising: instructions
to receive input data from the laser detector, the input data
indicating a portion of the laser detector receiving the beam;
instructions to determine, based at least in part on the input
data, that the slope of the beam should be adjusted; instructions
to transmit, via the second communication system, a notification
for reception by the first communication system, the notification
instructing the laser source to adjust the slope of the beam;
wherein the laser source is configured to adjust the slope of the
beam based at least in part upon the notification.
6. A laser source, comprising: a laser emitter configured to emit a
beam having a slope that is adjustable by the laser source; and a
communication system; wherein the laser source is configured to
receive, via the communication system, notification that the slope
of the beam should be adjusted and, to adjust the slope of the beam
emitted by the laser emitter, based at least in part on the
notification, and to transmit a message via the communication
system comprising information about an adjusted slope of the beam
emitted by the laser emitter.
7. The laser source recited by claim 6, wherein the laser emitter
emits a spot beam.
8. The laser source recited by claim 6, wherein the laser emitter
is a rotating laser emitter.
9. The laser source recited by claim 6, wherein the laser emitter
is configured to emit a tilting plane beam.
10. The laser source recited by claim 6, wherein the laser emitter
is configured to emit a beam that is raised and lowered to provide
conical reference surfaces of varying inclination.
11. A mobile station, comprising: a laser detector; a communication
system; and a processing system comprising a processor and a
computer-readable medium having encoded thereon a set of
instructions executable by the processing system to perform one or
more operations, the set of instructions comprising: instructions
to receive input data from the laser detector, the input data
indicating a portion of the laser detector receiving a beam from a
laser emitter; instructions to determine, based at least in part on
the input data, that the slope of the beam should be adjusted;
instructions to transmit, via the communication system, a
notification instructing a laser source to adjust the slope of the
beam; instructions to determine a position of the mobile station;
and instructions to calculate an elevation of the mobile station,
based at least in part on an adjusted slope of spot beam emitted by
the rotating laser emitter, the position of the mobile station, a
position of the laser source, and input data received from the
laser detector.
12. A method, comprising: providing, at a first location, a laser
source comprising a laser emitter; providing, at a second location,
a mobile station comprising a laser detector; emitting a beam from
the laser emitter, the slope of the beam being adjustable by the
laser source; receiving the emitted beam at a portion of the laser
detector; determining, based at least in part on the portion of the
laser detector receiving the emitted beam, that the slope of the
emitted beam should be adjusted; transmitting, from the mobile
station, a notification instruction instructing the laser source to
adjust the slope of the emitted beam; adjusting, at the laser
source, the slope of the emitted beam, based at least in part upon
the notification.
13. The method of claim 12, further comprising: determining a
velocity and direction of travel of the mobile station; wherein
determining that the slope of the emitted beam should be adjusted
comprises determining, based on the portion of the laser detector
receiving the emitted beam, the velocity of the mobile station, and
the direction of travel of the mobile station, that the slope of
the emitted beam should be adjusted.
14. The method of claim 12, wherein determining that the slope of
the emitted beam should be adjusted comprises determining an amount
by which the slope of the emitted beam should be adjusted, and
wherein adjusting the slope of the emitted beam comprises adjusting
the slope of the beam by the determined amount.
15. The method of claim 14, wherein determining an amount by which
the slope of the emitted beam should be adjusted comprises
determining an acceptable range of slope values for the emitted
beam, and wherein adjusting the slope of the emitted beam comprises
adjusting the slope of the beam to a value within the acceptable
range of slope values.
16. The method of claim 15, wherein the mobile station is a first
mobile station, and wherein adjusting the slope of the emitted beam
comprises selecting a value within the acceptable range of slope
values, wherein the selected value also allows a second mobile
station to receive the emitted beam.
17. The method of claim 16, further comprising notifying a second
mobile station of the adjusted slope of the emitted beam.
18. The method of claim 16, wherein selecting a value within the
acceptable range of slope values comprises prioritizing one of the
mobile stations over the other mobile station.
19. The method of claim 18, wherein the first mobile station is
mounted on a vehicle and wherein prioritizing one of the mobile
stations comprises prioritizing the first mobile station because
the first mobile station is mounted on a vehicle.
20. The method of claim 14, wherein determining an amount by which
the slope of the emitted beam should be adjusted comprises:
calculating a distance between the first location and the second
location; and determining the amount by which the slope of the beam
should be adjusted based at least in part on the portion of the
laser detector receiving the emitted beam and the distance between
the first location and the second location.
21. The method of claim 20, wherein the mobile station further
comprises a position-sensing device, the method further comprising
identifying, with the position-sensing device, the second
location.
22. The method of claim 21, wherein the position-determining device
comprises a global navigation satellite system ("GNSS")
receiver.
23. The method of claim 20, further comprising, receiving, at the
mobile station and from the laser source, identification of the
first location.
24. The method of claim 12, wherein the laser detector comprises a
substantially vertical array of laser sensors, and wherein
determining that the slope of the emitted beam should be adjusted
comprises: establishing an upper threshold value corresponding to a
first portion of the array of laser sensors; establishing a lower
threshold value corresponding to a second portion of the array of
laser sensors; determining a laser strike location value
corresponding to the portion of the laser detector receiving the
emitted beam; and comparing the laser strike location value with at
least one threshold value selected from the group consisting of the
upper threshold value and the lower threshold value.
25. The method of claim 12, wherein receiving the emitted beam at a
portion of the laser detector comprises: receiving, at a first
point in time, the emitted beam at a first portion of the laser
detector; and receiving, at a second point in time, the emitted
beam at a second portion of the laser detector.
26. The method of claim 25, wherein determining that the slope of
the emitted beam should be adjusted comprises: determining a first
laser strike location value corresponding to the first portion of
the laser detector; determining a second laser strike location
value corresponding to the second portion of the laser detector;
and comparing the first laser strike location value with the second
laser strike location value.
27. The method of claim 12, further comprising: calculating an
elevation of the mobile station, based at least in part on the
adjusted slope of the emitted beam and the portion of the laser
detector at which the emitted beam is received.
28. The method of claim 27, wherein the mobile station is mounted
on a vehicle, the method further comprising: setting a height of a
tool on the vehicle, based at least in part on the calculated
elevation of the mobile station.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit, under 35 U.S.C.
.sctn.119(e), of U.S. Provisional Application No. 61/139,149, filed
Dec. 19, 2008 by Kirk et al. and entitled "Laser Slope Adjustment",
the entire disclosure of which is incorporated herein by reference
for all purposes.
[0002] This application is related to commonly-owned, co-pending
U.S. patent application Ser. No. 12/135,623, field Jun. 9, 2008 by
Nicholas Talbot et al. and entitled "Laser Transmitter and Methods"
(the "'623 Application"), the entire disclosure of which is
incorporated herein by reference.
COPYRIGHT STATEMENT
[0003] A portion of the disclosure of this patent document contains
material that is subject to copyright protection. The copyright
owner has no objection to the facsimile reproduction by anyone of
the patent document or the patent disclosure as it appears in the
Patent and Trademark Office patent file or records, but otherwise
reserves all copyright rights whatsoever.
FIELD
[0004] The present disclosure relates, in general, to tools for
determining elevation, and more particularly, to laser-based tools
for determining elevation of a mobile station.
BACKGROUND
[0005] In the construction field, precise estimation of elevation
is of critical importance. For example, when grading a construction
site, the construction crew must know the elevation of the
equipment, in order to ensure that the site conforms to the plan
designed by the engineers and architects. These elevations may be
absolute, or they may be relative to some reference point on the
site.
[0006] Global positioning system ("GPS") receivers (or other global
navigation satellite system ("GNSS") equipment) are sometimes used
to estimate elevations. Limitations in this technology have
traditionally prevented the use of such systems for precise
elevation measurements, however. Although recent enhancements in
the technology have improved such systems, they often still cannot
attain the precision required for many tasks.
[0007] Laser technology is often used for elevation estimation as
well. Such systems typically will transmit a beam from a laser
emitter to a laser detector. Based on the known elevation of the
emitter, the slope of the beam (from the horizontal), and the
distance between the emitter and the detector, the elevation of the
detector (and, correspondingly, any equipment to which the detector
is attached) can be calculated. Such systems typically can offer
enhanced precision over GPS-based systems. However, existing
laser-based systems have problems dealing with any significant
changes in the elevation of the detector, which will cause the
emitted beam to miss the detector. Some systems implement a fan
beam (which effectively emits the beam over a broader area than a
rotating spot beam), allowing for greater flexibility in the
elevation of the detector relative to the emitter. Such systems are
not without problems either, however. In particular, the use of a
fan beam typically requires the use of more complex emitters and
also requires significant calculation to determine elevation based
on the received beam (since the emitted beam covers a broader
vertical spectrum at the point of reception). A fan beam design
also emits a larger fan beam, increasing power requirements and/or
reducing range of the possible detection.
[0008] A potential solution to these issues is the use of a
rotating spot beam in an emitter that is conditioned to calculate
the proper slope of the beam. One such solution provides the
emitter with GPS coordinates of the detector and forces the emitter
to calculate the proper slope of the beam based on the location of
the detector. This potential solution, however, requires
significant computing power in the emitter (raising costs) and
often prevents effective use of the emitter with multiple mobile
stations (each of which is in a different location and each of
which has its own detector) and reduces the ability to use other
information from the mobile station, for example expected terrain
that the detector is about to move over. This method also can have
significant radio transmission overhead as the emitter needs to be
in contact with the mobile station often Hence, this solution often
will require multiple, expensive emitters to accommodate the number
of detectors at use on a typical site.
[0009] A simpler solution would be to implement larger detectors,
which would allow for greater variation in detector elevation
before the detector ceases to receive the beam. Such detectors,
however, require a relatively large number of sensors, which are
quite expensive. Accordingly, the cost of implementing larger
detectors can quickly become prohibitive.
[0010] Accordingly, there is a need in the art for tools and
techniques that accurately and precisely estimate elevations while
addressing these types of issues.
SUMMARY
[0011] Certain embodiments, therefore, provide solutions
(including, without limitation, devices, systems, methods, software
programs, and the like) for estimating elevations. In an aspect,
certain of these tools can employ laser sources that do not require
significant computational power, reducing the cost of such tools.
Additionally, certain tools eliminate the need for large laser
detectors, further reducing the cost of the tools. An additional
benefit of some embodiments is the ability to support multiple
mobile stations from a single laser source, resulting in still
further cost savings.
[0012] Merely by way of example, some embodiments employ mobile
stations that are configured to identify, based on some or all of a
variety of factors, a situation in which the elevation of the
detector is likely to change to the extent that the slope of the
emitter needs to be adjusted to account for this change in
elevation. Such factors can include, without limitation, the
portion of the detector struck by the beam at a particular time
(compared, in some cases, to the portion of the detector struck at
a prior time and/or to threshold values); a direction and/or
velocity of the mobile station (or equipment to which it is
attached), which may be determined based on GNSS information; an
anticipated elevation change, and/or the like. In such situations,
the mobile station may inform the laser source that the slope of
the beam should be adjusted, and, optionally, inform the laser
source of an amount (or range of acceptable amounts) by which the
slope should be adjusted.
[0013] In other embodiments, the laser source may be configured to
receive the adjustment information from the mobile station and
adjust the slope of the laser accordingly. In particular cases, in
which the laser source supports multiple mobile stations, the laser
source can be configured to receive a range of acceptable
adjustments (or, from another perspective, a range of acceptable
slopes) and determine an appropriate slope adjustment based on the
needs of other mobile stations serviced by that laser source, so
that, for example, an adjustment to accommodate one mobile station
will not prevent other mobile stations from receiving the emitted
beam. In particular cases, where conflicts may be inevitable, the
laser source may be configured to prioritize one of the mobile
stations over the other(s). Optionally, the laser source can
transmit information about the adjusted slope of the beam to one or
more of the mobile station(s), which then might update their
elevation calculations accordingly.
[0014] The tools provided by various embodiments of the invention
include, without limitation, devices, methods, systems, and/or
software products that may be used to configure such
systems/devices and/or implement such methods. Merely by way of
example, a method might comprise one or more procedures, any or all
of which are executed by various components of a system.
Correspondingly, an embodiment might provide a system comprising
one or more devices configured with instructions to perform one or
more procedures in accordance with methods provided by various
embodiments. Similarly, a computer program might comprise a set of
instructions that are executable by a computer system (and/or a
processor therein) to cause a device to perform such operations. In
many cases, such software programs are encoded on physical and/or
tangible computer-readable media (such as, merely by way of
example, optical media, magnetic media, and/or the like).
[0015] Merely by way of example, one set of embodiments provides a
system for estimating the elevation of a vehicle (which might be,
for example, equipment used in earthmoving or digging operations,
or any other type of vehicle). The system might comprise a laser
source and one or more mobile stations. In a particular embodiment,
the laser source comprises a laser emitter, which is configured to
emit a beam having a slope that is adjustable by the laser source.
In certain embodiments, the laser emitter is a rotating laser
emitter, while in other embodiments, the emitted beam is a spot
beam. In some cases, the laser source also includes a communication
system, which might include a radio frequency transceiver (or any
other appropriate communication hardware). In other cases, the
laser source might include a position-sensing device (such as a
global navigation satellite system receiver, and/or the like).
[0016] A mobile station in accordance with some embodiments
comprises a laser detector, which might comprise an array of laser
sensors. In some embodiments, the array of lasers is arranged
substantially in a vertical configuration. The mobile station may
also include a position-sensing device and/or a communication
system as well. In a particular embodiment, the mobile station also
includes a processing system. The processing system, in an aspect,
may comprise a processor and a computer-readable medium having
encoded thereon a set of instructions that are executable by the
processing system to perform one or more operations.
[0017] Merely by way of example, the set of instructions might
include instructions to establish an upper threshold value
corresponding to a first portion of the array of laser sensors
and/or a lower threshold value corresponding to a second portion of
the array of laser sensors. The set of instructions might further
include instructions to receive input data from the laser detector,
and/or instructions to determine, based on the input data, a laser
strike location value corresponding to a portion of the laser
detector receiving the beam emitted by the laser emitter. In
certain embodiments, there may be instructions to compare the laser
strike location value with at least one threshold value selected
from the group consisting of the upper threshold value and the
lower threshold value. Moreover, the set of instructions, in
accordance with an embodiment, includes instructions to determine,
based at least in part on a comparison of the laser strike location
value with the at least one threshold value, an amount by which the
slope of the beam emitted by the laser emitter should be adjusted.
There may also be instructions to transmit, via the mobile
station's communication system, a notification for reception by the
laser source's communication system. In an aspect, the notification
might instruct the laser source to adjust the slope of the beam by
the determined amount.
[0018] Correspondingly, in accordance with some embodiments, the
laser source is configured to adjust, upon receipt of the
notification, the slope of the beam in accordance with the
notification. In some cases, the slope of the beam may be adjusted
over a period during which the beam will not be received by the
laser detector, and to transmit a message informing the mobile
station of an adjusted slope of the beam emitted by the laser
emitter. Further, the mobile station's processing system might
comprise further instructions to determine, based on input from the
position-sensing device, a position of the mobile station (which
might include a lateral position and/or an elevation), and/or to
calculate an elevation of the mobile station. In an aspect, this
calculation may be based at least in part on the adjusted slope of
the beam emitted by the rotating laser emitter, the position of the
mobile station, a position of the laser source, and/or input data
received from the laser detector. In some cases, there may also be
instructions to set a height of a tool on the vehicle, based at
least in part on the calculated elevation of the mobile
station.
[0019] A system in accordance with another set of embodiments
comprises a laser source and a mobile station. The laser source
might comprise a communication system and/or a laser emitter
configured to emit a beam having a slope that is adjustable by the
laser source. The mobile station might comprise a laser detector, a
communication system, and/or a processing system. The processing
system might comprise a processor and a computer-readable medium
having encoded thereon a set of instructions executable by the
processing system to perform one or more operations.
[0020] Merely by way of example, in an embodiment, the set of
instructions comprises instructions to receive input data from the
laser detector; this input data might indicate a portion of the
laser detector receiving the beam. The set of instructions might
further include instructions to determine, based at least in part
on the input data, that the slope of the beam should be adjusted,
and/or instructions to transmit a notification instructing the
laser source to adjust the slope of the beam. Accordingly, the
laser source might be configured to adjust the slope of the beam
based at least in part upon the notification.
[0021] A laser source in accordance with yet another set of
embodiments comprises a laser emitter configured to emit a beam
having a slope that is adjustable by the laser source, and a
communication system. The laser source might be configured to
receive, via the communication system, notification that the slope
of the beam should be adjusted. Based at least in part upon this
notification, the laser source might adjust the slope of the beam
emitted by the laser emitter, and/or might then transmit a message
via the communication system comprising information about an
adjusted slope of the beam emitted by the laser emitter.
[0022] Another set of embodiments provides methods, including
without limitation methods that may be implemented, at least in
part, by devices and/or systems provided by other embodiments. An
exemplary method comprises providing, at a first location, a laser
source comprising a laser emitter. The method might further
comprise providing, at a second location, a mobile station
comprising a laser detector. In some embodiments, the method also
comprises emitting a beam from the laser emitter, the slope of the
beam being adjustable by the laser source, and/or receiving the
emitted beam at a portion of the laser detector. In further
embodiments, the method also includes determining, based at least
in part on the portion of the laser detector receiving the emitted
beam, that the slope of the emitted beam should be adjusted. (In
some cases, determining that the slope of the beam should be
adjusted comprises determining an amount, or a range of acceptable
amounts, by which the slope of the beam should be adjusted.) The
method may also comprise transmitting, from the mobile station, a
notification instruction informing the laser source to adjust the
slope of the emitted beam.
[0023] In some embodiments, the method further comprises adjusting,
at the laser source, the slope of the emitted beam, based at least
in part upon the notification. In some cases, adjusting the slope
of the beam might comprise selecting a value within the acceptable
range of slope values; this selected value might also allow a
second mobile station to receive the emitted beam. In some cases,
selecting a value might comprise prioritizing one of the mobile
stations over the other mobile station(s). The method, then, might
comprise notifying the second mobile station of the adjusted slope
of the emitted beam.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] A further understanding of the nature and advantages of
particular embodiments may be realized by reference to the
remaining portions of the specification and the drawings wherein
like reference numerals are used throughout the several drawings to
refer to similar components. In some instances, a sublabel is
associated with a reference numeral to denote one of multiple
similar components. When reference is made to a reference numeral
without specification to an existing sublabel, it is intended to
refer to all such multiple similar components.
[0025] FIGS. 1A and 1B illustrate a system for determining
elevation of a mobile station, in accordance with various
embodiments.
[0026] FIG. 1C is a block diagram illustrating a laser source, in
accordance with various embodiments.
[0027] FIG. 1D is a block diagram illustrating a mobile station, in
accordance with various embodiments.
[0028] FIG. 2A is a plan drawing illustrating an
elevation-determination system comprising multiple mobile stations,
in accordance with various embodiments.
[0029] FIG. 2B is an elevation drawing illustrating the
elevation-determination system of FIG. 2A.
[0030] FIG. 3 is a process flow diagram illustrating a method of
determining elevation of a mobile station, in accordance with
various embodiments.
[0031] FIGS. 4 and 5 are process flow diagrams illustrating methods
of determining whether a laser slope should be adjusted, in
accordance with various embodiments.
[0032] FIG. 6 is a process flow diagram illustrating a method of
determining an amount (or an acceptable range of amounts) by which
a laser slope should be adjusted, in accordance with various
embodiments.
[0033] FIGS. 7 and 8 illustrate a system for determining elevation
of a mobile station, in accordance with various embodiments.
[0034] FIG. 9 is a generalized schematic diagram illustrating a
computer system, in accordance with various embodiments of the
invention.
DETAILED DESCRIPTION
[0035] While various aspects and features of certain embodiments
have been summarized above, the following detailed description
illustrates a few exemplary embodiments in further detail to enable
one of skill in the art to practice such embodiments. In the
following description, for the purposes of explanation, numerous
specific details are set forth in order to provide a thorough
understanding of the described embodiments. It will be apparent,
however, to one skilled in the art that other embodiments of the
present invention may be practiced without some of these specific
details. In other instances, well-known structures and devices are
shown in block diagram form. Several embodiments are described
herein, and while various features are ascribed to different
embodiments, it should be appreciated that the features described
with respect to one embodiment may be incorporated with other
embodiments as well. By the same token, however, no single feature
or features of any described embodiment should be considered
essential to every embodiment of the invention, as other
embodiments of the invention may omit such features.
[0036] A set of embodiments provide solutions (including without
limitation, devices, systems, methods, software programs, and the
like) for estimating elevations. (As used herein, the term
"estimating" elevation is used to describe any process in which the
elevation at a particular point--or of a particular mobile station,
tool, etc.--is measured, estimated, calculated, or otherwise
determined.) In particular, certain embodiments can provide
enhanced precision (in some cases, to a tolerance of 3 mm or less)
in measuring elevation, while providing for significant cost
savings over other solutions. Merely by way of example, some
embodiments employ laser sources that do not require significant
computational power, reducing the cost of such tools. As used
herein, the term "laser source" means any device that is capable of
emitting a focused beam of light (which may or may not reside in
the visible spectrum). In some cases, as described in further
detail below, a laser source may be configured to rotate, such that
the beam of light effectively is emitted as a plane of light, or
might otherwise be capable of emitting a planar beam. Additionally,
and/or alternatively, also as detailed below, a laser source might
comprise (or be incorporated within) one or more devices that
provide other functionality, including computing capabilities,
navigation capabilities, communication capabilities, and/or the
like.
[0037] Additionally, certain embodiments eliminate the need for a
mobile station with a large laser detector, further reducing the
cost of the tools. As used herein, the term "mobile station" refers
to any device or system that is capable of receiving an emitted
beam (e.g., a beam emitted from a laser source). Typically, a laser
detector is the component of the mobile station that actually
detects (receives) the emitted beam. In some cases, as detailed
below, a mobile station may have significant additional
capabilities and/or components, including computational
capabilities and/or components, navigational communication
capabilities and/or components, communication capabilities and/or
components, and/or the like, but these are not required. In many
cases, a mobile station (or components thereof) may be mounted on a
vehicle or other type of equipment. In other cases, certain
components of the mobile station may be incorporated within the
control and/or communication systems of the vehicle/equipment. In
other cases, however, a mobile station may be configured as
stand-alone and/or man-portable equipment, which can be used, for
example, by surveying crews. In some cases, the components of a
mobile station may be integrated into a single enclosure; in other
cases, these components may be distributed (for example, for a
mobile station mounted on a vehicle, the laser detector may be
mounted on the outside of the vehicle, while other components may
be installed within the vehicle's interior).
[0038] An additional benefit of some embodiments is the ability to
support multiple mobile stations from a single laser source,
resulting in still further cost savings. While the specified
embodiments described herein are often discussed in relation to
construction and/or surveying projects, the reader should
understand that the principles of various embodiments may be
employed in many different implementations, and that the invention
therefore is not limited to any particular application.
[0039] Merely by way of example, some embodiments employ mobile
stations that are configured to identify, based on some or all of a
variety of factors, a situation in which the elevation of the
detector is likely to change to the extent that the slope of the
emitter needs to be adjusted to account for this change in
elevation. Such factors can include, without limitation, the
portion of the detector struck by the beam at a particular time
(compared, in some cases, to the portion of the detector struck at
a prior time and/or to threshold values); a direction and/or
velocity of the mobile station (or equipment to which it is
attached), which may be determined based on GNSS information; an
anticipated elevation change, and/or the like. In such situations,
the mobile station may inform the laser source that the slope of
the beam should be adjusted, and, optionally, inform the laser
source of an amount (or range of acceptable amounts) by which the
slope should be adjusted.
[0040] To illustrate some of these concepts, FIG. 1A illustrates a
system 100 for estimating and/or calculating elevations, in
accordance with one set of embodiments. These elevations may be
absolute (e.g., feet above sea level) or relative to some specified
point (e.g., a reference point on a site being surveyed, graded,
etc.). The system 100 comprises a laser source 105 and a mobile
station 110. In the illustrated embodiment, the mobile station 110
is attached to (or incorporated in) a piece of equipment 115, which
might be a tractor, grader, front end loader, and/or any type of
equipment for which precise elevation information is beneficial. In
particular cases (as illustrated by FIG. 1), the mobile station 110
(or at least a component thereof, such as a laser detector) may be
installed on a tool 120 that is part of (or coupled to) the
equipment. Typically, such tools can include shovels, blades,
scoops, and the like (to name but a few examples); with the laser
detector (or mobile station 110) coupled with (or integrated with)
the tool 120, an operator can obtain elevation data not only for
the equipment 115, but for the tool 120 itself, allowing for
precise grading and/or digging operations, etc.
[0041] In operation, the laser source 105 emits a beam 125, which
is received by the mobile station 110, allowing for a determination
of the elevation of the mobile station 110 and/or, by extension of
the equipment 115 and/or tool 120. In a particular aspect, the
emitted beam 125 has a slope that is defined by its angle a from
the horizontal plane 130. (The angle a may either be negative,
indicating a slope below the horizontal plane 130 in the direction
of the mobile station 110, or positive, indicating a slope above
the horizontal plane 130 in the direction of the mobile station
110; the definition of positive and negative, in this context, is
of course arbitrary.)
[0042] The system 100 can be used to estimate the ground surface
elevation at the location of the mobile station 110. As a simple
example, the difference in elevation between the point on the
detector illuminated by the beam and the point from which the beam
is emitted is the horizontal distance between the emitter and the
detector multiplied by the tangent of the angle .alpha.. By adding
or subtracting (as appropriate) the known height of the bottom of
the detector from the ground surface (and/or the difference from
the bottom of the detector to the illuminated point) and the height
from emitter from the ground surface, the differences between the
ground surface elevation at the laser source 105 and the ground
surface elevation at the mobile station 110 may be calculated. By
adding this difference to a known absolute elevation of the ground
surface at the laser source 105, the absolute elevation of the
ground at the mobile station may be calculated. Using similar
calculations, a tool height may be set in order to achieve a
desired surface elevation at the mobile station 105.
[0043] As illustrated by the system 100' of FIG. 1B, when the
mobile station 110 moves, there is a possibility that the movement
of the mobile station 110 (either laterally and/or vertically) will
change the angle between the laser source 105 and the mobile
station 110; consequently, in this situation, the mobile station
110 will no longer be able to receive the emitted beam 125. To
remedy this problem, the beam (denoted 125' in FIG. 1B) should be
adjusted to a new slope (defined by angle .alpha.' in FIG. 1B) to
allow the mobile station 110 to continue to receive the emitted
beam 125'. Hence, in accordance with certain embodiments, and as
discussed in further detail below, the mobile station 110 is
configured to detect a situation in which the mobile station 110
will no longer be able to receive the beam 125 and,
correspondingly, to instruct the laser source 105 to adjust the
slope of the beam 125 accordingly.
[0044] FIG. 1C illustrates a block diagram of a laser source 105 in
accordance with one set of embodiments. The laser source 105
comprises a laser emitter 150, which is operable to generate and
emit a beam of light (which may or may not fall within the visible
spectrum, as noted above). A variety of commercially available
laser emitters may be used in accordance with different
embodiments. In various embodiments, the emitter 150 may be
operable to emit a spot beam, a fan beam, or any other type of beam
commonly known in the art. In particular aspects, as noted above,
the emitter 150 may be configured to rotate or otherwise
effectively produce a plane of light. In certain configurations,
the emitter 150 includes one or more mirrors, prisms, stepping
motors and/or other apparatus for adjusting the slope of the
emitted beam. Merely by way of example, a typical laser source will
emit a spot beam in a horizontal plane; advanced laser sources,
such as those used in accordance with certain embodiments, provide
a mechanism to tilt the emitter so as to project the beam or plane
of the emitted light at a desired slope. Thus, in a particular
aspect, the emitter 150 may be configured to emit a "tilting plane
beam"; in other words, the emitter 150 may be configured to emit a
plane of light (via rotation of a spot beam emitter, via a system
of mirrors and/or prisms, etc.) with a slope that can be
adjusted.
[0045] In another configuration, the emitter 150 may be configured
to oscillate vertically, effectively producing beam that is raised
and lowered to provide conical reference surfaces of varying
inclination. Merely by way of example, the '623 Application,
already incorporated by reference, describes a variety of
configurations of laser emitters (described therein as "laser
transmitters"); any of such emitters may be implemented in
accordance with various embodiments herein. Additionally and/or
alternatively, U.S. Pat. No. 6,643,004, filed Nov. 22, 2002 by
Detweiler et al., U.S. Pat. No. 6,870,698, filed Jul. 15, 2003 by
Detweiler et al., and U.S. Pat. No. 7,064,819, filed Jan. 25, 2005
by Detweiler et al. (the relevant portions of each of which are
incorporated herein by reference), describe laser emitters that are
configured to emit a "fan" beam. The laser source 105 may be
configured to employ such emitters, perhaps with appropriate
modification, to illuminate a laser detector in accordance with
certain embodiments.
[0046] In some embodiments, the laser source 105 also includes a
position-sensing device 155, which is operable to determine a
position (either absolute or relative to some reference point) of
the laser source 105. The position-sensing device 155 can be, in
accordance with various embodiments, any of a variety of devices
that can provide positional data. Such devices include, without
limitation, GNSS receivers, devices for triangulating a position
based on received signals (e.g., cellular communication devices,
etc.), and/or the like. The position-sensing device 155 can be used
to determine a position of the laser source 105; this position, as
discussed below, can be used along with other data, to calculate
the elevation of a mobile station.
[0047] The laser source 105 may also include a communication device
160 for communicating, inter alia, with one or more mobile
stations. In some aspects, the communication device 160 may include
a radio frequency ("RF") transceiver, which is operable to send
and/or receive RF signals. Any appropriate type of RF transceiver
may be used, in accordance with various embodiments (including,
without limitation, devices that only receive signals or devices
that only send signals), and the choice of frequency band for the
transmission is discretionary.
[0048] In some embodiments, the laser source 105 also includes a
processing system 165, which can comprise any of a variety of
special purpose computers and/or general purpose computers
configured with hardware, software, and/or firmware instructions to
perform procedures in accordance with various embodiments
(including the methods described below). An exemplary configuration
of a computer that may be implemented as the processing system 165
is described below with respect to FIG. 9. In certain embodiments,
the processing system 165 is responsible for overall control of the
laser source 105, including processing communications and/or data
received from or by the position-sensing device 155 and/or the
communication device 160, configuring the laser emitter 150 to
adjust the slope of the emitted beam, transmitting data (e.g., via
the communication device 160) for reception by mobile stations or
other devices, etc.
[0049] FIG. 1D provides a block diagram illustrating a mobile
station 110. As noted above, the components of the mobile station
110 may be integrated into a unitary device and/or may be
distributed among a plurality of devices (some of which, for
example, may be integrated with a piece of equipment to which the
mobile station is attached). In the illustrated embodiment, the
mobile station 110 comprises a laser detector 175, which is
operable to receive (i.e., detect) a beam of light (e.g., a laser
beam) emitted from a laser source, including without limitation a
laser source as described above.
[0050] In an exemplary embodiment, the laser detector comprises a
plurality of laser sensors 180, each of which individually can
detect an emitted beam. In some embodiments, the laser sensors 180
are arranged in a substantially vertical arrangement (although
there may be multiple detectors 180 at each level of the
substantially vertical strata; for ease of illustration, the laser
detector 175 is depicted on FIG. 1C as having a single detector 180
at each level). In an aspect, the sensors 180 may be divided into
subsets, such that a first subset of the detectors (for example,
sensors 180a and 180b) fall within one subset (considered the
"upper" portion of the laser detector 175), while a second subset
of the sensors 180 (for example, sensors 180c-180f) fall within a
second subset (considered the "middle" portion of the detector),
and a third subset (for example, sensors 180g and 180h) fall within
a third subset (considered the "lower" portion of the detector). In
a sense, these subsets are arbitrary and may be configured
differently for different implementations; the description of the
subsets provided herein is exemplary in nature and should not be
considered limiting.
[0051] In some embodiments, the laser detector 175 is configured to
determine which portion of the detector 175 (i.e., which subset of
the sensors 180) is receiving an emitted beam at any given point in
time and output that information. In other embodiments, the laser
detector 175 may be configured to provide output about which
specific sensor(s) 180 are receiving an emitted beam, and other
components of the mobile station 110 might be configured to
interpret that output to determine a portion of the detector 175
illuminated by the emitted beam. A variety of techniques may be
used to make this determination.
[0052] The mobile station 110 may also include a position-sensing
device 185 and/or a communication device 190. As noted above, these
components may be incorporated within a unitary mobile station 110
and/or may be distributed (e.g., integrated within the control
and/or communication systems of a vehicle or other equipment). In
an aspect, the position-sensing device 185 and/or communication
device 190 may be similar in architecture and/or function to those
respective devices discussed above with respect to FIG. 1B.
[0053] The mobile station 110 may also include a processing system
195, which can comprise any of a variety of special purpose
computers and/or general purpose computers configured with
hardware, software, and/or firmware instructions to perform
procedures in accordance with various embodiments (including the
methods described below). An exemplary configuration of a computer
that may be implemented as the processing system 195 is described
below with respect to FIG. 9. In certain embodiments, the
processing system 195 is responsible for overall control of the
mobile station 110, including processing communications and/or data
received by or from the position-sensing device 185, the
communication device 190, and/or the laser detector 175,
calculating an elevation of the mobile station 110 (and/or the
equipment, tool, etc., to which it may be attached), transmitting
data (e.g., via the communication device 160) for reception by
laser sources, other mobile stations or devices, etc., controlling
operation of equipment and/or tools to which the mobile station 110
may be attached (and/or providing data to a control system of such
equipment and/or tools, to enable the control systems to control
the equipment and/or tools based on the provided data), and/or the
like.
[0054] In accordance with some embodiments, a laser source may be
able to support multiple mobile stations, for example, by providing
an emitted beam that is receivable by each of the mobile stations.
To illustrate this functionality, FIG. 2A depicts a plan view of a
system 200 comprising a laser source 105 and two mobile stations
110, and FIG. 2B depicts an elevation drawing of the same system
200. (While FIGS. 2A and 2B, for convenience, illustrate only two
mobile stations 110, it should be appreciated that various
embodiments may support any number of mobile stations.)
[0055] In the system 200, the laser source 105 (which might
comprise a rotating laser emitter, to name but one example)
effectively emits a beam 125 in a plane. (In the case of a rotating
laser, the beam might be a spot beam that, due to the rapid
rotation of the laser, effectively presents an emitted plane normal
to the emitter's axis of rotation.) At certain points, the beam
(depicted as line 125a) is received by a first mobile station 110a,
while at other points, the beam (depicted as line 125b) is received
by a second mobile station 110b. As shown in FIG. 2B, depending on
the alignment of the first mobile station 110a, the laser source
105, and the second mobile station 110b, the same laser "plane" can
be received by both mobile stations 110.
[0056] In the event, however, that one of the mobile stations (for
example, the second mobile station 110b) moves, however, the slope
of the emitted beam 125 may need to be adjusted, as described above
(with respect to FIG. 1B) and, in further detail, below. This
adjustment often will affect the elevation measurements for the
first mobile station 110a. If the adjustment is relatively major,
the beam 125a may no longer be received by the first mobile station
110a at all. Even if the adjustment is relatively minor (such that
the beam 125a continues to be received by the first mobile
station), however, it is likely that elevation calculations for the
first mobile station 110a will be affected, since the beam 125a
most likely will be received by a different portion of the first
mobile station's 110a detector.
[0057] Certain embodiments can use a variety of techniques to
mitigate these issues. For example, as described in further detail
below, in some cases, when the second mobile station 110b requests
adjustment of the beam's slope, it might provide a range of
acceptable adjustments. The laser source 105, in selecting a new
slope for the beam 125, may be configured to take into account the
impact any adjustment might have on other mobile stations (e.g.,
the first mobile station 110a), for example, by selecting a slope
within the acceptable range for the second mobile station 110b that
still will allow the mobile station 110a to receive the beam 125.
Additionally, and/or alternatively, the laser source 105 might also
communicate to the first mobile station 110a a value of the
adjusted slope of the beam 125, so that the first mobile station
can revise its calculation model to account for the different slope
of the received beam 125a. (In some embodiments, the revision of
the calculation model may be performed automatically by the
processing system of the first mobile station 110a, based on the
information received from the laser source.)
[0058] Another possible technique to resolve such conflicts is the
prioritization of one mobile station (e.g., the second mobile
station 110b) over other mobile stations (e.g., 110a) serviced by
the laser source 105. Hence, in the event of an irreconcilable
conflict between the mobile stations 110a and 110b, the laser
source 105 will elect to adjust the slope of the emitted beam so as
to allow the prioritized mobile station 110b to continue to receive
the emitted beam 125b, even if that means that the other mobile
stations (e.g., 110a) will no longer be able to receive the beam.
In certain cases, the laser source 105 may be configured to provide
notification to any mobile stations that will no longer be able to
receive service. In some cases, these mobile stations may be
configurable (e.g., by adjustment of a mounting stand, etc.) to be
adjusted in height to receive a beam on the adjusted slope. In such
cases, the mobile station 110a might provide (on a display device,
for example) instructions to allow an operator to adjust the height
of the mobile station 110a, and/or if automated height adjustment
is available, to adjust the height automatically.
[0059] In yet other cases, the laser source 105 may be sufficiently
sophisticated to be able to emit the beam on different slopes in
different directions. Merely by way of example, in the case of a
rotating emitter, the emitter may be configurable to emit the beam
on a first slope in a first direction, and then to change the
emission angle during the rotation, such that the beam is omitted
on a different slope in another direction. This process can be
repeated, such that the emitted beam oscillates between a first
slope in a first direction (to be received by a first mobile
station) and a second slope in a second direction (to be received
by a second mobile station). The laser source 105, in some cases,
may use this technique to provide service to two mobile stations
110 that might otherwise have an irreconcilable conflict. In this
situation, the laser source 105 might be configured to adjust only
one of these slopes in response to instructions received from a
mobile station.
[0060] FIGS. 3-6 illustrate various methods that can be used to
determine an elevation of a mobile station, to determine whether a
laser's slope should be adjusted, and/or by how much a laser's
slope should be adjusted, in accordance with certain embodiments.
While the methods of FIGS. 3-6 are illustrated, for ease of
description, as different methods, it should be appreciated that
the various techniques and procedures of these methods can be
combined in any suitable fashion, and that, in some embodiments,
the methods depicted by FIGS. 3-6 can be considered interoperable
and/or as portions of a single method. Moreover, while the methods
illustrated by FIGS. 3-6 can be implemented by (and, in some cases,
are described below with respect to) the systems 100 and 100' of
FIGS. 1A and 1B and/or the system 200 of FIGS. 2A and 2B (or
components thereof), these methods can be implemented using any
suitable hardware implementation. Similarly, while the systems 100
and 100' of FIGS. 1A and 1B and/or the system 200 of FIGS. 2A and
2B (and/or components thereof) can operate according to the methods
illustrated by FIGS. 3-6 (e.g., by executing instructions embodied
on a computer-readable medium), the systems 100 and 200 can also
operate according to other modes of operation and/or perform other
suitable procedures.
[0061] FIG. 3 illustrates a method 300 of estimating elevations
using a laser source and one or more mobile stations. The method
300 comprises emitting a beam (e.g., a beam of light, as described
above) from an emitter in a laser source (block 305). The beam, in
an aspect, has a slope that is adjustable by the laser source, as
described above. The method 300 further comprises receiving the
emitted beam at a mobile station (block 310). More particularly, in
some cases, the beam will be received by a laser detector (and,
specifically, one or more laser sensors in the laser detector) at
the mobile station. At block 315, the method 300 comprises
determining that the slope of the emitted beam should be adjusted
(and/or, in some cases, determining an amount by which the slope of
the beam should be adjusted).
[0062] In a particular set of embodiments, this determination is
made at the mobile station that receives the beam. Merely by way of
example, the processing system in the mobile station may be
configured with software, hardware and/or firmware instructions
that can be executed by the processing system to determine that the
slope of the beam should be adjusted (and/or an amount or range of
amounts by which the slope should be adjusted). There are a variety
of ways in which this determination can be made. Merely by way of
example, FIGS. 4 and 5, respectively, illustrate two methods for
determining that the slope of a received beam should be adjusted,
and/or by how much the slope should be adjusted.
[0063] FIG. 4, for example, illustrates a method 400 of determining
that the slope of a received beam should be adjusted and,
optionally, for determining an amount of adjustment (or range of
acceptable adjustments and/or slopes). The method 400 may be
performed, for example, by the processing system of a mobile
station, based perhaps on instructions executed by that processing
system. The method 400 comprises, in one embodiment, establishing
an upper threshold value corresponding to an upper portion of the
mobile station's detector (e.g., a subset of laser sensors on the
upper portion of the detector) (block 405) and/or establishing a
lower threshold value corresponding to a lower portion of the
mobile stations detector (e.g., a subset of laser sensors on the
upper portion of the detector) (block 410).
[0064] The way in which these threshold values are defined often
will depend on the nature of the laser detector and its output.
Merely by way of example, the detector may be configured to output
a different value (or provide output on different leads) depending
on which sensors receive a beam. The upper and lower threshold
values thus might correspond to the values (or leads) corresponding
to particular sensors that can be considered as a boundary for the
upper and/or lower portions of the detector. To illustrate one
example, by reference to FIG. 1D, sensor 180b might be defined as
the upper threshold. If the detector 175 provides output indicating
that any sensor above the sensor 180b, such as sensor 180a (or in
some cases, depending on how the threshold is defined, any sensor
above or including sensor 180b), is receiving the emitted beam, the
output from the detector 175 will be considered to meet or exceed
the upper threshold. Similarly, the sensor 180g might be defined as
the lower threshold, such that output from the detector 175
indicating that a sensor (such as the sensor 180h) below the sensor
180g (and/or the sensor 180g itself, depending on how the threshold
is defined) is receiving the emitted beam, that output would be
considered to meet or exceed the lower threshold.
[0065] From this example, it should be appreciated that there are
many techniques which the upper and/or lower thresholds are
defined; for purposes of various embodiments, all that matters is
that the upper and/or lower thresholds correspond to some portion
at the upper and/or lower end of the detector, such that reception
of a beam at or beyond the threshold indicates that the beam is
striking the detector near either the upper or lower end of the
detector.
[0066] The method 400 further comprises receiving (typically at the
mobile station's processing system) input data from the laser
detector (block 415). This input data generally will provide an
indication that the laser detector is receiving the emitted beam,
as well as indicate a portion (e.g., by reference to FIG. 1D, one
or more sensors 180) of the detector receiving the emitted beam.
Based on this input data, the processing system determines a laser
strike location value (block 420), which corresponds to the portion
of the detector receiving the emitted beam (referred to herein as
the laser or beam "strike location" on the detector). In some
aspects, the laser strike location value might refer to a distance
from some reference point on the detector (such as the bottom of
the detector, etc.) or another relative value, such as an elevation
difference between the strike point and some reference elevation
(which might be the elevation of the base of the mobile station,
the elevation of the laser source, etc.). In other cases, the laser
strike location value might be expressed as an absolute elevation
value (e.g., a distance from sea level, etc.). This laser strike
location value is then compared with at least one threshold value
(block 425), which can be the upper threshold and/or the lower
threshold described above.
[0067] In some embodiments, the processing system might also be
configured to determine a velocity and/or direction of travel of
the mobile station (block 430). Merely by way of example, if the
mobile station comprises a position-sensing device, input from the
position-sensing device can be used to determine the direction
and/or velocity of travel of the mobile station (e.g., by comparing
position values at multiple points in time). This determination may
be performed internally in the position-sensing device, which might
then provide the velocity and/or directional information to the
processing system; alternatively, the position-sensing device might
merely provide multiple location data points, and the processing
system might be configured to calculate the velocity and/or
directional data.
[0068] The method 400 further comprises determining that the slope
of the emitted beam (referred to herein as the "beam slope") should
be adjusted (block 435). In some cases, the processing system at
the mobile station makes this determination, although in accordance
with other embodiments, a different device (such as the laser
source) might make this determination. The determination of whether
the beam slope should be adjusted can take into account a variety
of factors. Merely by way of example, in some cases, it may be
determined that the beam slope should be adjusted based only on
whether the laser strike location value exceeds one of the
threshold values. For instance, if the beam currently has a
negative slope (below horizontal) and the laser strike location
value exceeds the upper threshold, the beam slope should be
increased (in absolute terms), such that the beam would strike the
detector at a lower point after adjustment.
[0069] In a more sophisticated example, information other than
laser strike values might be included in determining whether the
beam slope should be adjusted. Merely by way of example, in some
cases, the velocity and/or direction of the mobile station (and/or
the equipment/vehicle to which it is attached) may be considered
(either alone or along with other factors) when determining whether
the beam slope should be adjusted. For instance, if the mobile
station is not moving, it may be determined that the beam slope
need not be adjusted, even if the beam is striking the detector
outside one of the thresholds. As a more complex example, if the
beam strike location value is at one of the threshold values, and
the direction and/or velocity of the mobile station indicate that
the beam is moving further from the center of the detector (for
example, if the mobile station is below the laser source and the
beam strike location value is at or above the threshold, and if the
velocity and direction of the mobile station's movement indicate
that the mobile station is moving toward the laser source), it
might be determined that the beam will soon miss the detector, such
that the beam slope should be adjusted.
[0070] In some cases, additional data might be taken into account
as well. Merely by way of example, if the mobile station is
programmed with an existing topology of the site (or a desired
topology of the site), the velocity and direction of movement of
the mobile station might be used to calculate a future elevation of
the mobile station, and this future elevation, perhaps in
combination with laser strike location data, can be used to make a
determination that the beam slope should be adjusted. Merely by way
of example, if the topological data, in combination with the
directional and/or velocity data, indicate that the mobile station
soon will be rising in elevation, it may be determined that the
beam slope should be adjusted upward to accommodate this change in
mobile station elevation.
[0071] In yet other cases, a simpler model may be used to determine
whether a laser slope should be adjusted. For example, FIG. 5
illustrates a method 500 of determining whether the beam slope
should be adjusted in accordance with another set of embodiments.
The method of FIG. 5 is an example of a technique that does not
require the establishment of threshold values. (It should be noted
that many such techniques may be used, in accordance with various
embodiments.)
[0072] The method 500 comprises receiving (e.g., at a processing
system) a first set of input data (e.g., from a laser detector)
about a first strike location value (block 505), corresponding to a
first portion of the laser detector receiving the emitted beam at a
first point in time. The method 500 further comprises receiving a
set of input data from the laser detector (block 510),
corresponding to a second portion of the detector receiving the
emitted beam at another point in time. The method 500 further
comprises comparing the first laser strike location value with the
second laser strike location value (block 515). Based on this
comparison, a determination can be made that the slope of the
emitted beam should be adjusted (block 520). Merely by way of
example, if the first laser strike location value indicates that
the beam was received in the middle of the detector, and the second
laser strike location value indicates that the beam was received at
the top end of the detector, it may be determined that that slope
of the beam should be adjusted in an upward direction, so as to
bring the laser strike location back toward the center (or perhaps
the lower portion) of the detector.
[0073] In some cases, it may be desirable to determine not only
that a beam slope should be adjusted, but also by how much the
slope should be adjusted. Accordingly, FIG. 6 illustrates a method
600 of determining an appropriate amount (or a range of acceptable
amounts) by which the slope should be adjusted. (It should be noted
that this adjustment can be viewed in relative terms, i.e., an
adjustment from a current slope, or in absolute terms, i.e., a
slope--or range of slopes--that would provide acceptable
performance, irrespective of the current slope. The distinction
between a relative amount of adjustment and an absolute adjustment
is arbitrary, and the same techniques may be used to determine
either value; the only difference is whether the current slope is
taken into account.) Typically, the method 600 will be performed
(e.g., by the processing system in a mobile station and/or laser
source) after it has been determined (as described above, for
example) that the slope of the emitted beam should be adjusted.
[0074] The method 600 comprises, in some embodiments, receiving, at
the mobile station, data about a position of the laser emitter
(e.g., data about the position of the laser source) (block 605).
This data typically will have been transmitted from the laser
source, which might generate the data based on user input, data
received from/by a position-sensing device, and/or the like. At
block 610, the method comprises determining the position of the
mobile station, or more precisely, the position of the laser
detector (which typically will be the same as, or similar to, the
position of the mobile station). Typically, this position will be
determined based on data received by/from a position-sensing device
that is incorporated within (or in communication with) the mobile
station. (It should be noted that, while the method 600 describes
the process for an embodiment in which the mobile station
calculates the amount by which the beam slope should be adjusted,
other embodiments might perform this calculation at the laser
source, or any other appropriate location. In such cases, the
position data for the mobile station and laser source can provided
to any such location, using transmissions similar to those
described above.)
[0075] The method 600 comprises calculating a distance from the
laser detector to the laser emitter (block 615). Typically, this
distance is calculated based on the determined positions of the
emitter and detector, and the distance may be a lateral
(horizontal) distance, disregarding any changes in elevation
between the two devices. This is not necessary in all embodiments,
however, and other techniques for measuring and/or calculating this
distance may be used. Merely by way of example, in some cases,
laser rangefinding (based, perhaps, on the beam emitted by the
laser source) can be used to determine a linear distance (which
typically would not disregard elevation changes) between the
emitter and the detector.
[0076] At block 620, the method 600 comprises determining an
acceptable range of slope values for the emitted beam (as used
herein, the term "slope value" refers to any value or identifier
that describes, either quantitatively or qualitatively, the slope
of the emitted beam; merely by way of example, the slope value may
be expressed in degrees from horizontal, degrees from present
slope, preset slope identifiers each of which identify a certain
slope angle, and/or emitter tilt increments, or any other
appropriate units). In an embodiment, this calculation is based on
one or more of several factors. Merely by way of example, in some
cases, the known current slope of the beam (which might be
transmitted from the laser source to the mobile station using the
respective communication systems of the two devices, in embodiments
in which the mobile station determines an acceptable range of slope
values), the strike location of the beam on the detector, the
endpoints of a preferred strike region on the detector (which might
correspond to the thresholds described above), the direction of
movement of the mobile station (or detector), and/or the velocity
of movement of the mobile station (or detector) may be considered
when determining the acceptable range of slopes for the emitted
beam.
[0077] As a simple example, in a situation in which the emitted
beam currently is striking the detector above the upper threshold,
determining a range of acceptable slopes might comprise determining
a first beam slope that corresponds to the upper threshold and a
second beam slope that corresponds to the lower threshold. To
illustrate, consider FIG. 7, which illustrates an emitter 150 and a
detector 175, with an emitted beam 125, having a slope a, which
strikes the detector at a strike point 705, which is above an upper
threshold 710. An acceptable range of beam slope values might fall
between .alpha.' and .alpha.'', which correspond to emitted beams
125' and 125'', which strike the detector 175 at the upper
threshold 710 and lower threshold 715, respectively. To calculate
this range, the method 600 might first calculate a difference y in
elevation between the emission point 720 of the beam 125 and the
strike point 705. This value y can be calculated as the horizontal
distance x between the emitter 150 and the detector 175, multiplied
by the tangent of the known slope .alpha.. To identify the
elevation difference y' between the emission point 720 and the
upper threshold 710, the method would merely add the known distance
between the strike point 705 and the upper threshold 710 to the
value y (already calculated above). A similar procedure could be
used to calculate the elevation difference y'' between the emission
point 720 and the lower threshold 715. The value of .alpha.' for a
beam 125' striking at the upper threshold 710 then can be
calculated as the inverse tangent of y'/x, while the value of a''
for a beam 125'' striking at the lower threshold 715 can be
calculated as the inverse tangent of y''/x. (If the linear distance
between the emission point 720 and the strike point is used, rather
than the horizontal distance, similar calculations can be performed
by substituting the sine and inverse sine functions, respectively,
for the tangent and inverse tangent functions described above.)
[0078] In other cases, similar calculations could be performed
while taking into account factors such as mobile station movement
velocity and direction, or estimated future changes in mobile
station elevation (for example, by adjusting the upper threshold
710 and/or lower threshold 715 to account for these factors, or by
substituting for the thresholds other desired strike locations,
based on these factors).
[0079] At block 625, the method 600 comprises determining an amount
by which the beam slope should be adjusted. In some embodiments,
this determination may be made at the mobile station, while in
other embodiments, the determination may be made at the laser
source (or any other appropriate location). In an aspect of some
embodiments, this amount may be determined based, at least in part,
on a comparison of the strike point of the beam on the detector
(represented by a laser strike point elevation value, as noted
above) with one or more thresholds. Merely by way of example, in
some cases, the slope of the emitted beam may be adjustable in
increments, and if the strike point falls above an upper threshold,
the determination of an amount by which the beam slope should be
adjusted might merely comprise determining that the beam slope
should be adjusted downward by one increment (or by more than one
increment, depending on the distance between the threshold and the
strike point). This technique might be performed iteratively, with
the beam slope being adjusted (and a new determination being made
that the beam slope should be adjusted further) incrementally until
the beam slope falls at an acceptable point on the laser
detector.
[0080] In other cases, the determination of the amount by which the
beam slope should be adjusted might entail a more complex
technique. Merely by way of example, as described in further detail
below, the mobile station might determine an acceptable range of
beam slope values (and/or determine an acceptable range of slope
adjustments by subtracting the current slope value from the range
of acceptable slope values), and the laser source might determine
an amount by which the beam slope should be adjusted, based,
perhaps, on other factors such as the need to provide service to
other mobile stations, etc.). Alternatively and/or additionally, a
mobile station might select an appropriate amount by which the
slope should be adjusted using a process similar to that described
above for determining an appropriate range of slope values, except
that the mobile station might select a discrete point on the laser
detector as the desired location for the new strike point and
calculate an amount by which the slope should be adjusted to force
the laser source to emit a beam that will strike the detector at
the desired strike location.
[0081] As noted above, in some embodiments, the determination of
whether the beam slope should be adjusted (and, optionally, an
amount or range of acceptable amounts by which the beam slope
should be adjusted) may be performed at the mobile station. In such
embodiments, the mobile station transmits, for reception by the
laser source, a notification that the slope of the emitted beam
should be adjusted (block 320), and the laser source receives this
notification (block 325). In an aspect of some embodiments, this
notification is transmitted and/or received by the communication
systems of the mobile station and laser source, respectively, based
on control of those communication systems by the processing systems
of the respective devices.
[0082] The nature of the notification generally will depend on the
embodiment. In some cases, the notification might merely consist of
an instruction to adjust the slope of the emitted beam, perhaps
with additional information specifying whether the beam slope
should be adjusted up or down. In other embodiments, a more
detailed notification might be transmitted, which can include
information about an amount by which the beam slope should be
adjusted and/or a range of acceptable adjustment amounts, which
might be calculated by the mobile station as described above.
(These adjustment amounts might be expressed as relative values,
such as an adjustment from the current beam slope, or as absolute
values, such as a desired beam slope value or range of acceptable
slope values.)
[0083] In certain embodiments, upon reception of the notification
that the slope of the emitted beam should be adjusted, the laser
source typically will adjust the slope of the beam accordingly, as
described in further detail below. Before doing so, however, the
laser source, in some embodiments, may perform some preliminary
operations.
[0084] Consider, for example, a situation in which a laser source
is configured to support multiple mobile stations. In such
situations, it may be the case that the requested slope adjustment
might create a conflict between the needs of two (or more) served
mobile stations. As noted above, there are several techniques that
may be used to prevent and/or mitigate such a conflict.
[0085] For instance, in some cases, the method 300 may comprise
prioritizing one mobile station over the other(s) (block 330).
Merely by way of example, a laser source (or, more precisely in
many cases, the processing system of the laser source) may be
configured with a prioritized list of mobile stations (which may be
identified by an identifier and/or a station type, such as
vehicular, handheld, etc.) and/or the location of each mobile
station currently being served. In some cases, for example, a
mobile station may transmit its identifier and/or its location to
the laser source that is serving the mobile station; the laser
source may, in turn, store a table of served mobile stations and/or
their corresponding locations. The laser source may prioritize the
mobile stations based on user input (e.g., input identifying a
mobile station as a high-priority mobile station) and/or based on a
set of stored rules (e.g., a rule specifying that that a
vehicle-based mobile station should be prioritized over a handheld
or man-portable mobile station, etc.).
[0086] When the laser source receives an instruction to adjust the
slope of the emitted beam, the laser source may be configured to
identify the mobile station transmitting the instruction (e.g.,
based on an identifier included with the notification that the
slope should be adjusted) and determine whether that mobile station
has a higher priority than any other currently-served mobile
stations. If that is the case, the laser source may adjust the
slope of the beam accordingly, as described further below. If the
mobile station requesting the slope adjustment has a lower priority
than another mobile station served by the laser source, the laser
source may determine that the slope of the beam should not be
adjusted (or should not be adjusted at that time), and optionally
may notify the requesting mobile station accordingly.
[0087] In addition to, or as an alternative to, prioritizing one
mobile station over others, the laser source may be configured to
select a beam slope that can accommodate two or more of the served
mobile stations (block 335). Merely by way of example, if a mobile
station transmits a notification that the beam slope should be
adjusted, along with a range of acceptable slope values, the laser
source may select, from the range of acceptable slope values, a
beam slope that will accommodate the requesting mobile station, but
that will also allow one or more of the other served mobile
stations to continue to receive the emitted beam. (Of course, if
the laser source is not serving any other mobile stations, it may
select a slope adjustment arbitrarily, such as selecting the slope
adjustment in the middle of the specified range, selecting the
maximum adjustment from the range, selecting the minimum adjustment
from the range, etc.)
[0088] In some cases, the laser source (and/or the processing
system of the laser source) makes this determination by identifying
the location(s) of the served mobile stations other than the mobile
stations requesting the slope adjustment (either by consulting a
table of stored locations for served mobile stations or by
transmitting a message requesting location information and
receiving the location information in return). In addition, the
laser source may obtain from the non-requesting mobile stations
information about the beam strike location on the detectors of
those mobile stations and/or the thresholds of those detectors--for
instance, the laser source may request such information from the
non-requesting mobile stations, which may perform a procedure
similar to that described above with respect to FIG. 4 and/or 5 and
provide beam strike information to the laser source, which can
determine whether the adjusted slope would allow the non-requesting
mobile station(s) to continue to receive the emitted beam.
Alternatively, the laser source may request that a mobile station
determine whether a proposed adjusted beam slope would still allow
that mobile station to receive the beam (in which case, the mobile
station could perform a procedure similar to that described with
respect to FIG. 6 to determine whether the proposed adjusted slope
would allow the mobile station's detector to receive the beam on
the adjusted slope). Other techniques may be used as well to
determine whether a proposed adjusted slope would accommodate one
or more served mobile stations other than the station requesting
the slope adjustment.
[0089] There are, of course, other techniques for resolving
conflicts between the needs of two served mobile stations. Merely
by way of example, some lasers may be configured to provide
multi-planar emissions (for example, by adjusting an emitter to
project a beam on a first slope when aimed in a first direction and
readjusting the emitter to project a beam on a second slope in a
second direction, in effect oscillating the slope of the beam as
the emitter rotates). In such cases, the laser source might adjust
the slope of the beam in one plane, but not adjust (or adjust by a
different amount) the slope of the beam in another plane. From
these examples, one of skill in the art can appreciate that various
embodiments can employ many different techniques to resolve
conflicts between served mobile stations.
[0090] Upon receiving the notification that the slope of the
emitted beam should be adjusted (and/or, optionally, selecting a
slope value from a range of acceptable values, as described above),
the laser source adjusts the slope of the emitted beam (block 340).
As noted above, the laser source includes an adjustment mechanism
(which might include one or more stepping motors, etc.) for
adjusting the angle of the laser emitter. In an embodiment, the
processing system of the laser source provides appropriate
instructions to the adjustment mechanism for adjusting the slope of
the emitted beam in the selected amount (or to match a selected
angle). In some cases, the slope of the beam is adjusted over a
period in time in which the beam will not be received by the
detector (e.g., while the emitter is not emitting, or while a
rotating emitter is facing away from the detector), so as not to
confuse the mobile station with a beam that is moving in the
vertical direction.
[0091] In some embodiments, the laser source transmits a
notification message informing one or more of the served mobile
stations that the slope of the emitted beam has been adjusted
(block 345). In some cases, for example when the laser source has
selected a slope from a range of acceptable slopes, or when the
laser source serves mobile stations other than the mobile station
requesting the adjustment, the notification message may specify an
amount of adjustment (and/or the new value) of the slope of the
emitted beam. In other cases, such as when the laser source serves
only one mobile station, and that mobile station has specified an
amount of adjustment, the notification may not need to include
information about the adjusted slope (and in fact the notification
itself may be unnecessary). In some cases, a single notification
message may be transmitted for reception by all served mobile
stations, while in other cases, separate notifications may be
transmitted for reception by each mobile station. In some cases,
the notification message may include other information (such as the
location of the laser source, the elevation of the laser emitter,
etc.).
[0092] In certain cases, a mobile station may need to adjust its
elevation calculations to account for the adjusted slope of the
laser emitter. Hence, in a set of embodiments, if a mobile station
determines that the slope of the emitted beam has changed (based on
reception of a notification message from the laser source, by
identifying a change in the laser strike location after requesting
a slope adjustment, etc.), the processing system of the mobile
station may adjust its calculation model accordingly. Merely by way
of example, by reference to FIG. 8, before adjustment of the
emitted beam 125, the mobile station (not pictured on FIG. 7) could
calculate its elevation by determining the elevation difference y
between the strike location 705 and the elevation of the emitter
720. As noted above, this elevation difference may be expressed,
for example, as
y=xtan .alpha. (Eq. 1)
where x is the horizontal distance from the emitter 720 to the
detector 175, and .alpha. represents the angle between the
horizontal plane 130 and the slope of the beam 125.
[0093] In embodiments in which the laser source effectively emits a
conical or other non-planar beam, such as some of the embodiments
described in the '623 Application, already incorporated by
reference, a timing mechanism, several of which are disclosed in
the '623 Application, may be implemented to determine the slope
(described as "elevation angle" in the '623 Application) of the
beam for purposes of calculating the elevation difference between
the laser source and the mobile station. Merely by way of example,
the '623 Application discloses the use of strobes to provide timing
information to enable the mobile station (described as a "laser
receiver" in the '623 Application) to determine the slope of the
beam. In another embodiment, the '623 Application describes the use
of a fixed time schedule for a complete cycle of raising and
lowering the beam. The '623 Application further describes the use
of radio transmissions to continuously transmit the slope of the
beam from the laser source to the mobile station. Any of these
techniques, as well as others, can be used to provide necessary
information to allow the mobile station to determine the elevation
difference between the laser source and the mobile station,
especially in the case of a non-planar beam.
[0094] By adding (or subtracting, as appropriate), this elevation
difference y to/from the emitter elevation, the elevation of the
strike location 705 can be determined. In addition, the height
y.sub.1 of the strike location from the ground 810 is known (or can
be calculated--for example, the mobile station might be programmed
with a value for the distance from a reference point on the
detector 175, such as the top or bottom of the detector 175, to the
ground 810, and the distance from the strike location 705 to the
reference point on the detector 175 can be determined by the mobile
station based on the output from the detector 175). By subtracting
this distance y.sub.1 from the calculated elevation of the laser
strike location 705, the elevation of the ground at the mobile
station (i.e., the elevation of the mobile station) can be
determined.
[0095] If, however, the beam slope angle a is adjusted so that the
emitted beam 125' has a new slope .alpha.', the beam 125' will have
a new strike location 805, which will have a new height y.sub.1'
from the ground 810. The elevation difference y' between the new
strike location 805 and the emitter 720 will be different from the
elevation difference y between the original strike location 705 and
the emitter 720 (assuming the mobile station has not moved and the
elevation of the ground 810 therefore remains the same). To account
for this change (from y to y'), the mobile station must update its
calculation model to employ the new beam slope (represented by
.alpha.'), rather than the original beam slope (represented by
.alpha.), such that
y'=xtan .alpha.' (Eq. 2)
It should be noted, of course, that other calculation models may be
used to determine the elevation of the mobile station, and that the
example above is provided merely for illustrative purposes.
[0096] Once the calculation model has been updated, the mobile
station can calculate the elevation of the mobile station (or, more
precisely, the elevation of the ground on which the mobile station
sits). In some cases, as noted above, this will require determining
the distance (either a horizontal distance or a straight-line
distance) between the emitter and the beam strike location on the
detector. Hence, the method 300 may comprise identifying a position
of the mobile station and/or a position of the laser source (block
350), as described above, for example.
[0097] The method 300 may also comprise, at block 355, calculating,
at the mobile station, an elevation of the mobile station. This
calculation may be based on one or more factors including, without
limitation, the positions(s) of the mobile station and/or the laser
source, the distance between the two, the elevation of the laser
source (or a component thereof, such as the laser emitter), the
slope of the beam emitted by the laser emitter (which may be a
slope that has been adjusted as described above), and/or input data
received from the laser detector (e.g., data about the laser strike
location on the laser detector). Merely by way of example, the
calculation model described above may be used to calculate the
elevation of the mobile station.
[0098] As noted above, in many cases, a mobile station may be
attached to (or integrated within) a vehicle or other equipment
that includes a tool, such as a shovel, blade, scoop, etc. In such
cases, the mobile station may be configured to provide data and/or
instructions for setting the height of the tool (relative to the
mobile station, the equipment, the ground, etc.) (block 360).
Merely by way of example, as noted above, a mobile station (or some
components thereof) may be integrated with the control system; in
many cases, such control systems are designed to set the height of
a tool so as to produce a ground surface at a certain elevation.
Based on a comparison of the elevation of the mobile station (which
can be calculated as described above) with a desired ground
elevation at the point of the mobile station, the control system
for the equipment can be configured to set a height of the tool,
such that the operation of the tool produces a new ground surface
at the desired elevation.
[0099] FIG. 9 provides a schematic illustration of one embodiment
of a computer system 900 that can perform the methods provided by
various other embodiments, as described herein, and/or can function
as a processing system for a laser source, a mobile station, an
equipment control system, and/or the like It should be noted that
FIG. 9 is meant only to provide a generalized illustration of
various components, any or all of which may be utilized as
appropriate. FIG. 9, therefore, broadly illustrates how individual
system elements may be implemented in a relatively separated or
relatively more integrated manner.
[0100] The computer system 900 is shown comprising hardware
elements that can be electrically coupled via a bus 905 (or may
otherwise be in communication, as appropriate). The hardware
elements may include one or more processors 910, including without
limitation one or more general-purpose processors and/or one or
more special-purpose processors (such as digital signal processing
chips, graphics acceleration processors, and/or the like); one or
more input devices 915, which can include without limitation a
mouse, a keyboard and/or the like; and one or more output devices
920, which can include without limitation a display device, a
printer and/or the like.
[0101] The computer system 900 may further include (and/or be in
communication with) one or more storage devices 925, which can
comprise, without limitation, local and/or network accessible
storage, and/or can include, without limitation, a disk drive, a
drive array, an optical storage device, solid-state storage device
such as a random access memory ("RAM") and/or a read-only memory
("ROM"), which can be programmable, flash-updateable and/or the
like. Such storage devices may be configured to implement any
appropriate data stores, including without limitation, various file
systems, database structures, and/or the like.
[0102] The computer system 900 might also include a communications
subsystem 930, which can include without limitation a modem, a
network card (wireless or wired), an infra-red communication
device, a wireless communication device and/or chipset (such as a
Bluetooth.TM. device, an 802.11 device, a WiFi device, a WiMax
device, cellular communication facilities, etc.), and/or the like.
The communications subsystem 930 may permit data to be exchanged
with a network (such as the network described below, to name one
example), other computer systems, and/or any other devices
described herein.
[0103] The communications subsystem 930 may also provide relatively
local communications, using any of a variety of local
communications technologies, such as serial communications,
parallel communications, a universal serial bus ("USB"), other
dedicated local communication facilities, and/or the like. In some
cases, the communications subsystem 930 may be integrated with the
bus 905, and therefore might provide direct communication between
the bus 905 and other components outside the computer system (such
as other components of a mobile station, laser source, etc.). In a
particular set of embodiments, the communications subsystem 930 may
serve as a communication system for a mobile station and/or a laser
source that incorporates the computer system 900, while in other
embodiments, the mobile station/laser source might implement a
communication system separate from the computer system 900.
[0104] In many embodiments, the computer system 900 will further
comprise a working memory 935, which can include a RAM or ROM
device, as described above. The computer system 900 also can
comprise software elements, shown as being currently located within
the working memory 935, including an operating system 940, device
drivers, executable libraries, and/or other code, such as one or
more application programs 945, which may comprise computer programs
provided by various embodiments, and/or may be designed to
implement methods, and/or configure systems, provided by other
embodiments, as described herein. Merely by way of example, one or
more procedures described with respect to the method(s) discussed
above might be implemented as code and/or instructions executable
by a computer (and/or a processor within a computer); in an aspect,
then, such code and/or instructions can be used to configure and/or
adapt a general purpose computer (or other device) to perform one
or more operations in accordance with the described methods.
[0105] A set of these instructions and/or code might be stored on a
computer-readable storage medium, such as the storage device(s) 925
described above. In some cases, the storage medium might be
incorporated within a computer system, such as the system 900. In
other embodiments, the storage medium might be separate from a
computer system (i.e., a removable medium, such as a compact disc,
etc.), and/or provided in an installation package, such that the
storage medium can be used to program, configure and/or adapt a
general purpose computer with the instructions/code stored thereon.
These instructions might take the form of executable code, which is
executable by the computer system 900 and/or might take the form of
source and/or installable code, which, upon compilation and/or
installation on the computer system 900 (e.g., using any of a
variety of generally available compilers, installation programs,
compression/decompression utilities, etc.) then takes the form of
executable code.
[0106] It will be apparent to those skilled in the art that
substantial variations may be made in accordance with specific
requirements. For example, customized hardware might also be used,
and/or particular elements might be implemented in hardware,
software (including portable software, such as applets, etc.), or
both. Further, connection to other computing devices such as
network input/output devices may be employed.
[0107] As mentioned above, in one aspect, some embodiments may
employ a computer system (such as the computer system 900) to
perform methods in accordance with various embodiments of the
invention. According to a set of embodiments, some or all of the
procedures of such methods are performed by the computer system 900
in response to processor 910 executing one or more sequences of one
or more instructions (which might be incorporated into the
operating system 940 and/or other code, such as an application
program 945) contained in the working memory 935. Such instructions
may be read into the working memory 935 from another
computer-readable medium, such as one or more of the storage
device(s) 925. Merely by way of example, execution of the sequences
of instructions contained in the working memory 935 might cause the
processor(s) 910 to perform one or more procedures of the methods
described herein.
[0108] The terms "machine-readable medium" and "computer-readable
medium," as used herein, refer to any medium that participates in
providing data that causes a machine to operate in a specific
fashion. In an embodiment implemented using the computer system
900, various computer-readable media might be involved in providing
instructions/code to processor(s) 910 for execution and/or might be
used to store and/or carry such instructions/code (e.g., as
signals). In many implementations, a computer-readable medium is a
physical and/or tangible storage medium. Such a medium may take
many forms, including but not limited to, non-volatile media,
volatile media, and transmission media. Non-volatile media
includes, for example, optical and/or magnetic disks, such as the
storage device(s) 925. Volatile media includes, without limitation,
dynamic memory, such as the working memory 935. Transmission media
includes, without limitation, coaxial cables, copper wire and fiber
optics, including the wires that comprise the bus 905, as well as
the various components of the communication subsystem 930 (and/or
the media by which the communications subsystem 930 provides
communication with other devices). Hence, transmission media can
also take the form of waves (including without limitation radio,
acoustic and/or light waves, such as those generated during
radio-wave and infra-red data communications).
[0109] Common forms of physical and/or tangible computer-readable
media include, for example, a floppy disk, a flexible disk, hard
disk, magnetic tape, or any other magnetic medium, a CD-ROM, any
other optical medium, punchcards, papertape, any other physical
medium with patterns of holes, a RAM, a PROM, and EPROM, a
FLASH-EPROM, any other memory chip or cartridge, a carrier wave as
described hereinafter, or any other medium from which a computer
can read instructions and/or code.
[0110] Various forms of computer-readable media may be involved in
carrying one or more sequences of one or more instructions to the
processor(s) 910 for execution. Merely by way of example, the
instructions may initially be carried on a magnetic disk and/or
optical disc of a remote computer. A remote computer might load the
instructions into its dynamic memory and send the instructions as
signals over a transmission medium to be received and/or executed
by the computer system 900. These signals, which might be in the
form of electromagnetic signals, acoustic signals, optical signals
and/or the like, are all examples of carrier waves on which
instructions can be encoded, in accordance with various embodiments
of the invention.
[0111] The communications subsystem 930 (and/or components thereof)
generally will receive the signals, and the bus 905 then might
carry the signals (and/or the data, instructions, etc. carried by
the signals) to the working memory 935, from which the processor(s)
905 retrieves and executes the instructions. The instructions
received by the working memory 935 may optionally be stored on a
storage device 925 either before or after execution by the
processor(s) 910.
[0112] While certain features and aspects have been described with
respect to exemplary embodiments, one skilled in the art will
recognize that numerous modifications are possible. For example,
the methods and processes described herein may be implemented using
hardware components, software components, and/or any combination
thereof Further, while various methods and processes described
herein may be described with respect to particular structural
and/or functional components for ease of description, methods
provided by various embodiments are not limited to any particular
structural and/or functional architecture but instead can be
implemented on any suitable hardware, firmware and/or software
configuration. Similarly, while various functionality is ascribed
to certain system components, unless the context dictates
otherwise, this functionality can be distributed among various
other system components in accordance with the several
embodiments.
[0113] Moreover, while the procedures of the methods and processes
described herein are described in a particular order for ease of
description, unless the context dictates otherwise, various
procedures may be reordered, added, and/or omitted in accordance
with various embodiments. Moreover, the procedures described with
respect to one method or process may be incorporated within other
described methods or processes; likewise, system components
described according to a particular structural architecture and/or
with respect to one system may be organized in alternative
structural architectures and/or incorporated within other described
systems. Hence, while various embodiments are described with--or
without--certain features for ease of description and to illustrate
exemplary aspects of those embodiments, the various components
and/or features described herein with respect to a particular
embodiment can be substituted, added and/or subtracted from among
other described embodiments, unless the context dictates otherwise.
Consequently, although several exemplary embodiments are described
above, it will be appreciated that the invention is intended to
cover all modifications and equivalents within the scope of the
following claims.
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